变形链球菌延伸因子（EF-Tu）tuf基因的克隆及序列分析

发布时间：2019-04-13 09:32

【摘要】： 变形链球菌(Streptococcus mutans，以下简称变链)是龋病的主要致病菌之一，耐酸性是其关键的毒力因子。变链作为口腔中最耐酸的细菌，目前多数研究都集中在与其粘附性相关基因的研究，，但对于开发变链耐酸性基因则显得不足，变形链球菌在pH值低至4.0时仍能代谢蔗糖产酸，有助于维持菌斑的低pH环境，使牙面脱矿破坏，而其他很多致龋菌则不能在pH值小于5.0的酸性环境中进行糖酵解。变链在低pH环境中能够继续生长、代谢的分子机制尚未明了，其中包括在蛋白质合成过程中负责肽链延伸的延伸因子(EF-Tu)，还需要大量的科研工作来揭示其作用机制。本试验以该基因作为靶点，采用PCR方法，以变链染色体DNA为模板扩增延伸因子tuf基因，得到tuf基因全长共1197bp，克隆至pMD18-T载体后进行序列分析，登陆Gene-Bank申请序列号为EF536028，目的是寻找一个新的与变形链球菌耐酸性相关的基因，为进一步研究变链延伸因子在变链耐酸过程中的作用机制奠定良好基础，为龋病的防治提供新的思路。
[Abstract]:Streptococcus mutans (Streptococcus mutans,) is one of the main pathogenic bacteria of caries. Acid tolerance is the key virulence factor of Streptococcus mutans. As the most acid-resistant bacteria in oral cavity, most of the studies focus on the genes related to its adhesion, but it is insufficient to develop the variable-chain acid-tolerant genes. Streptococcus mutans can still metabolize sucrose and produce acid at pH 4.0, which is helpful to maintain the low pH environment of plaque and demineralize the tooth surface. However, many other caries-causing bacteria can not glycolysis in acidic environment with pH less than 5.0. Variable chains can continue to grow in low pH environment, the molecular mechanism of metabolism is not clear, including the extension factor (EF-Tu), which is responsible for the extension of peptide chain in the process of protein synthesis, and a great deal of research work is needed to reveal its mechanism. In this experiment, the extension factor tuf gene was amplified by PCR method with the variable strand chromosome DNA as the template. The total length of the tuf gene was 1197bp. After cloning into the pMD18-T vector, the gene was cloned into the pMD18-T vector for sequence analysis. The sequence number of the tuf gene was EF536028,. The aim of this study is to find a new gene related to acid tolerance of Streptococcus mutans, and to lay a good foundation for further study of the mechanism of variable chain extension factor in the process of acid tolerance of Streptococcus mutans, and to provide a new way of thinking for the prevention and treatment of caries.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2007
【分类号】：R378

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